Please help me find the time-complexity of below recursive algo. I have guessed for first two return statements.Please correct me if I am wrong. But I can't find time-complexity of third return statement because it will loop till we get a factorial of NUM contining 0 and 7.
public class Check
{
static long NUM = 11;
public static void main(String[] args)
{
System.out.print(find007(NUM));
}
static long find007(long n){
if(is007(n)) //O(1)
return n;
if(n+NUM<n) //O(1)
return 0;
return find007(n+NUM); //O(?)
}
static boolean is007(long n){
while(n!=0 && (n%10==0 || n%10==7)) //O(log n)
n=n/10;
return n==0;
}
}
Pseudo-code:
static long find007(long n){
check if number or its multiple consists of only 0 or 7.
if yes, return the answer/number
return n;
//if not, keep checking for the other multiples of NUM
i.e n+NUM (here NUM=11, so it will keep adding 11 to itself till 77)
return find007(n+NUM);
}
static boolean is007(long n){
continue till n!=0 and n%10==0 OR n%10==7
n=n/10;
return true if n==0;
}
